1. Field of the Invention
The present invention relates to a nonvolatile memory system, nonvolatile memory device, data read method, and data read program thereof that are featured in data reading from the nonvolatile memory device especially when a written file is damaged due to errors such as data retention failure or the like.
2. Discussion of the Related Arts
In recent years, a nonvolatile memory device loading a nonvolatile memory has been expanding its market as a memory card for a digital camera and a cellular phone. Then following an increase in the storage capacity of the memory card, its application has been expanding from recording of, for example, a data file, still image, or the like, which requires a small capacity, to recording of a motion picture, which requires large capacity.
However, a NAND type flash memory mainly used as a nonvolatile memory of the memory card essentially has a possibility of a data retention error. Thus, data to be recorded is provided with an error correcting code (hereinafter, also referred to as ECC) and written into the flash memory, and also data correction is performed based on the error correcting code at the time of reading, thereby ensuring the data in the event of a data retention error.